1. Field of the Invention
This invention relates to a method for boring a hole in the ground by the use of an excavating machine and an apparatus therefor and, more particularly, to a boring method and an apparatus therefor suitable for the use in construction of a tunnel, laying of a pipe, renewal of an existing pipeline, construction of a vertical shaft and formation of a longitudinal hole or the like.
2. Description of the Prior Art
As one of methods for boring a hole in the ground, Japanese Patent Public Disclosure (KOKAI) No. Sho 59-192193 has disclosed a press-in method using an excavating machine including a shield body and a conical rotor disposed in front of the shield body for eccentric motion about an axis of the shield body. According to this press-in method, by making a thrust act on the shield body while eccentrically moving the rotor, a hole is formed while the earth and sand in front of the shield body are thrust aside by the rotor.
As another one of methods for boring a hole in the ground, Japanese Patent Public Disclosures (KOKAI) No. Sho 60-242295 and No. Sho 61-102999 have disclosed an excavating method using an excavating machine including a shield body, excavating means disposed in front of the shield body so as to be rotatable about an axis of the shield body and means for discharging substances excavated by the excavating means to the rear of the shield body. According to this excavating method, the ground is excavated by making a thrust act on the shield body while rotating the excavating means and then a hole is formed by discharging the excavated substances onto the ground surface. The excavated substances discharged onto the ground surface are subjected to predetermined treatment and thereafter transported to a predetermined place to be dumped.
However, the former method, that is, the press-in method involves a problem in that a large thrust should be made to act on the shield body since a large reaction acts on the rotor when the shield body is propelled. 0n the contrary, the latter excavating method involves a problem in that it is high in cost since all of the excavated substances are discharged onto the ground surface.